Add infrastructure for partial layouts

Source/core/dom/Document.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
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     // Special support for editing
     PassRefPtr<CSSStyleDeclaration> createCSSStyleDeclaration();
     PassRefPtr<Text> createEditingTextNode(const String&);
 
     void recalcStyle(StyleChange = NoChange);
     void updateStyleIfNeeded();
     void updateStyleForNodeIfNeeded(Node*);
     void updateLayout();
     void updateLayoutIgnorePendingStylesheets();
+    void tryPartialUpdateLayoutIgnorePendingStylesheets(RenderObject*);
     PassRefPtr<RenderStyle> styleForElementIgnoringPendingStylesheets(Element*);
     PassRefPtr<RenderStyle> styleForPage(int pageIndex);
 
     void updateDistributionForNodeIfNeeded(Node*);
 
     // Returns true if page box (margin boxes and page borders) is visible.
     bool isPageBoxVisible(int pageIndex);
 
     // Returns the preferred page size and margins in pixels, assuming 96
     // pixels per inch. pageSize, marginTop, marginRight, marginBottom,
@@ skipping 911 matching lines @@
 inline bool Node::isDocumentNode() const
 {
     return this == documentInternal();
 }
 
 Node* eventTargetNodeForDocument(Document*);
 
 } // namespace WebCore
 
 #endif // Document_h